Posted
by
timothy
on Thursday December 08, 2011 @06:34PM
from the plaster-of-mars-would-be-really-expensive dept.

First time accepted submitter RCC42 writes "The Opportunity rover has found evidence that liquid water once flowed on Mars, through the discovery of gypsum — a mineral that can only be formed in the presence of water. Though other evidence in the past has suggested highly acidic water on Mars, this is the first evidence for water with a pH suitable for life as we know it."

Are we talking just a thin crust, or are we talking "gypsum quarry" size formations?

The reason I ask, is gypsum contains absurd quantities of chemically bound water. If mars has a higher calcium ion concentration than earth does, and had liquid oceans at one time, it is possible that with the carbon dioxide rich atmosphere and lack of techtonic plate movement that a sizable quantity of the ocean turned into "concrete" rather than drying up.

This would mean that much of the light elements (hydrogen, etc) might have escaped being blown off the atmosphere.

This is exciting news for science fiction writers that like to dream about terraforming. Creating techtonic activity would create the geomagnetic dynamo the planet needs, and as a consequence of the subduction and volcanism, huge quantities of water vapor would be expelled as a volcanic gas.

About all the planet would need would be ammonia, for the missing nitrogen. (Doesn't titan have an ammonia atmosphere? Wink, nudge.)

This does not mean the planet would go from lifeless desert to habitable overnight, as the gasses relased would be inhospitable to oxygen dependant life like us, but certain algae species like chlorella can survive in 100% C02 atmospheric concentrations as long as there is sunlight and water. Chlorella is well researched, fully genomically sequenced, and already has engineered varieties. A strain intended to rapidly convert the atmosphere to something a bit less toxic would actually be fairly plausible.

Smashing titan into mars would probably be a bad thing. (A very, very bad thing. That is, unless you like the idea of scattering huge chunks of rock into space. See for instance, the collision simulation for the hypothesis of earth's moon's formation.)

Better, would be to go ahead and nudge the moon out of saturns orbit, have it fall into the inner solar system, sweep a wide orbit of the sun, then fall into orbit around mars.

Best to use a trans ecliptic orbit, so that the falling body doesn't adversely effect other inner planet systems.

Once in martian orbit, titan's gravity would cause intense mantle heating of the red planet. It is likely that titan's atmosphere would freeze and snow out after being dislodged from saturn's orbit, due to the lack of tidal heating while it transits. Mars' tidal forces would be miniscule compared to saturn's, though being in the habitable zone might be enough to heat titan enough to reconstitute the atmosphere. Unknown.

It is concievable that with both bodies in the habitable zone, that both bodies could be actively terraformed.

Titan is presumed to have a silicate core, and not an iron nickle one like mars and earth. This means that it wouldn't disrupt the new martian magnetosphere. (Like our moon doesn't.)

Mars is more massive than titan, and if the atmosphere reconstitutes, mars might just rip it off titan.

I want to clarify that I can't think of anything more important to our species than the ability to leave this planet indefinitely. What we have learned about our universe and the geological history of this planet is that eventually something will destroy Earth or at least alter it so drastically that it cannot support human life any longer. The big questions are when and how that will happen. Maybe a giant asteroid will hit us, Yellowstone may blow it's top again, or we damage the current ecosystem so badly that Earth becomes inhospitable. So I really want make clear, I am very pro space travel.

However, that is why we need to be reasonable. We need to gather more information on space in general, test materials that can withstand the extreme conditions in outer space, and research advanced propulsion technologies. This kind of research can be done without human beings physically present. The cost of keeping a sack of meat alive on a 9 month trip to Mars is absurd. If we ever consider spending that much money it should all be spent on research and development until the actual trip to Mars is no longer costly and what is then based on old and reliable technology.

Besides, if we began planning a trip to Mars right now, by the time the actually went, we would likely have some very sophisticated Rovers. Just imagine what they could do if the whole budget was spent on launching advanced rovers and probes instead of on keeping people alive.

I don't think you understand how much payload would be required just to support the human.

It's on the order of 100 tonnes per person. More mass will be needed overall, but that can be obtained from Mars itself.

For example, the rovers produce less than 1 kWh/day even under optimal conditions. In the winter when it goes into hibernation it's down to less than 0.16 kWh/day or like a 6-7 watt light bulb. How many solar panels do you think it'd take to sustain a human?

3000 calories (for a very active person) corresponds to roughly 3.5 kWh/day. The Mars Science Laboratory (MSL) generates about 2.5 kWh/day and about 45-50 kWh/day of waste heat (with half life of almost 90 years).

Of course, that does measure true power needs. Humans need to eat food, so there's going to be at least a factor of ten loss converting solar energy into food energy. On the plus side, that can be grown, say in a pressurized greenhouse or LED-lit chamber. Near Earth the rule of thumb is 100 square meters (m2) is roughly enough garden space to feed an active person (and ten times what area you need to provide oxygen for that person). Since solar intensity drops by half, then one would expect that 200 m2 probably would do on Mars and there are various tricks to drop that amount.

In exchange for this modest mass and complexity, you get the best tools, that humanity has to offer. Keep in mind also that unmanned probes such as the MSL are increasing in power consumption. So it's reasonable to expect that power consumption over the mission will enter the range where manned missions are viable. And that's an additional aspect of manned missions. They have a lot of synergies with high power missions.